/*
 * Copyright 2010 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.hbase;

import java.io.IOException;

/**
 * Coprocess interface.
 */
public interface Coprocessor {
	static final int VERSION = 1;

	/** Highest installation priority */
	static final int PRIORITY_HIGHEST = 0;
	/** High (system) installation priority */
	static final int PRIORITY_SYSTEM = Integer.MAX_VALUE / 4;
	/** Default installation priority for user coprocessors */
	static final int PRIORITY_USER = Integer.MAX_VALUE / 2;
	/** Lowest installation priority */
	static final int PRIORITY_LOWEST = Integer.MAX_VALUE;

	/**
	 * Lifecycle state of a given coprocessor instance.
	 */
	public enum State {
		UNINSTALLED, INSTALLED, STARTING, ACTIVE, STOPPING, STOPPED
	}

	// Interface
	void start(CoprocessorEnvironment env) throws IOException;

	void stop(CoprocessorEnvironment env) throws IOException;
}
